CN110606857A - A-D-A type organic small molecule based on nine-ring fused aromatic hydrocarbon and preparation method and application thereof - Google Patents

Abstract

The invention discloses an A-D-A type organic micromolecule based on nine-ring fused aromatic hydrocarbon and a preparation method and application thereof. The A-D-A type organic micromolecule has a structural formula shown in a formula I. The preparation method is characterized in that intermediate M1 and 2- (3-oxygen-2, 3-dihydro-1H-indene-1-ylidene) malononitrile are subjected to Knoevenagel condensation reaction under the action of a solvent and a catalyst to obtain the compound. The A-D-A type organic micromolecule realizes the regulation and control of the photoelectric properties of the micromolecule such as molecular structure, absorption spectrum, band gap, front line molecular orbital energy level and the like by changing the type of the side chain on the central nucleus of the IDBDT, has the adjustable absorption spectrum, simultaneously has good thermal stability and high open-circuit voltage, and can be applied to the preparation of organic solar cells.

Description

A-D-A type organic small molecule based on nine-ring fused aromatic hydrocarbon and preparation method and application thereof

Technical Field

The invention relates to the technical field of organic solar cells, and relates to an A-D-A type organic small molecule based on nine-ring fused aromatic hydrocarbon, a preparation method and application thereof, in particular to an A-D-A type organic small molecule based on nine-ring fused aromatic hydrocarbon indacenodibi (benzodithiophene) (IDBDT for short) unit, a preparation method and application thereof.

Background

Organic Solar Cells (OSCs) have the advantages of low cost, light weight, simple fabrication process, easy large-area fabrication, and the like, and are receiving much attention. In recent years, Polymer Solar Cells (PSCs) based on organic small molecule acceptor materials have been developed rapidly, and their energy conversion efficiency (PCE) has been increasing, which is currently over 15%. Wherein, the development of novel high-efficiency small molecule acceptor materials is the key for improving PCE.

The Indacenobithiophene (IDDT) fused by Indacenobithiophene (IDT) and benzodithiophene (IDBDT for short) is a polycyclic fused nonacyclic aromatic hydrocarbon, has good planarity and electron donating performance, and can be used as a central electron donating D unit for constructing an A-D-A type small molecule acceptor material. At present, relevant documents and patents have not designed and synthesized A-D-A type small molecular materials with an IDBDT unit as a central D core. Therefore, the design and synthesis of A-D-A type small molecules by IDBDT units and the application of the A-D-A type small molecules as receptor materials in PSCs have important theoretical and practical research significance.

Disclosure of Invention

The invention aims to overcome the defects of the prior art, particularly overcomes the defects of few types and narrow application fields of organic micromolecule solar cell materials based on the IDBDT of the nine-ring fused aromatic hydrocarbon, and provides an A-D-A type organic micromolecule based on the nine-ring fused aromatic hydrocarbon, a preparation method and application thereof. The preparation method is simple, the reaction yield of each step is high, and the method can be applied to the preparation of organic solar cells.

In order to solve the technical problem, the invention provides an A-D-A type organic small molecule based on nine-ring fused aromatic hydrocarbon, wherein the A-D-A type organic small molecule has a structural formula shown in the following formula I:

in the formula I: r is selected from any one of the following groups:

—C₆H₁₃、—C₈H₁₇、—C₁₀H₂₁、—C₁₂H₂₅、—C₁₄H₂₉、—OC₆H₁₃、—OC₈H₁₇、—OC₁₀H₂₁、—OC₁₂H₂₅、—OC₁₄H₂₉、

as a general technical concept, the present invention also provides a preparation method of the above a-D-a type organic small molecule based on the nonacyclic fused aromatic hydrocarbon, wherein the a-D-a type organic small molecule is obtained by performing Knoevenagel condensation reaction on intermediate M1 and 2- (3-oxo-2, 3-dihydro-1H-inden-1-ylidene) malononitrile under the action of a solvent and a catalyst, the 2- (3-oxo-2, 3-dihydro-1H-inden-1-ylidene) malononitrile is denoted as IC, and the intermediate M1 has a structural formula shown in formula II below:

in the formula II: r is selected from any one of the following groups:

—C₆H₁₃、—C₈H₁₇、—C₁₀H₂₁、—C₁₂H₂₅、—C₁₄H₂₉、—OC₆H₁₃、—OC₈H₁₇、—OC₁₀H₂₁、—OC₁₂H₂₅、—OC₁₄H₂₉、

the synthetic route of the A-D-A type organic micromolecule is as follows:

in the preparation method, the molar ratio of the intermediate M1 to IC is preferably 1: 4-6.

In the preparation method, the molar ratio of the catalyst to the intermediate M1 is preferably 11-14: 1.

In the preparation method, preferably, the catalyst is one of pyridine, piperidine and triethylamine.

In the above preparation method, preferably, the solvent is one of chloroform and acetonitrile.

In the preparation method, preferably, the intermediate M1 is prepared by the following method:

s1-1, reacting the compound 1 with n-butyllithium and tributyltin chloride at-78 ℃ to obtain a compound 2;

s1-2, mixing the compound 2, the compound 3 and tetratriphenylphosphine palladium, and heating to react to obtain a compound 4;

s1-3, reacting the compound 4 with n-butyllithium and 1-bromo-4-hexylbenzene at-78 ℃ to obtain a compound 5;

s1-4, reacting the compound 5 with N-butyllithium and N, N-dimethylacetamide at-78 ℃ to obtain an intermediate M1;

the compound 1 is

The compound 2 is;

the compound 3 is:

the compound 4 is:

the compound 5 is:

the compound M1 is:

the synthetic route of the intermediate M1 is as follows:

in the preparation method, preferably, in S1-1, the molar ratio of the compound 1, n-butyllithium and tributyltin chloride is 1: 1-2.

In the preparation method, preferably, in S1-2, the molar ratio of the compound 2 to the compound 3 to the tetratriphenylphosphorated-palladium is 3-4: 1: 0.03-0.05.

In the preparation method, preferably, in S1-3, the molar ratio of the compound 4, n-butyllithium and 1-bromo-4-hexylbenzene is 1: 4-6: 5-7.

In the preparation method, preferably, in S1-4, the molar ratio of the compound 5, N-butyllithium and N, N-dimethylacetamide is 1: 4-8: 6-10.

As a general technical concept, the invention also provides an application of the A-D-A type organic small molecule in the preparation of a solar cell.

In the above application, preferably, the method of application is:

(1) spin-coating a conductive film of PEDOT/PSS polymer on the anode;

(2) spin-coating an optically active layer formed by blending A-D-A type organic micromolecules based on the nine-ring fused aromatic hydrocarbon and PBDB-T;

(3) vacuum evaporating metal calcium as a cathode modification layer;

(4) and evaporating cathode metal aluminum to obtain the solar cell.

Compared with the prior art, the invention has the advantages that:

(1) the invention provides an organic small molecule with A-D-A configuration based on a nonacyclic fused aromatic hydrocarbon IDBDT, wherein the A-D-A type organic small molecule takes a nonacyclic aromatic hydrocarbon IDBDT unit fused by Indacenodithiophene (IDT) and Benzodithiophene (BDT) as a central core D, and 2- (3-oxygen-2, 3-dihydro-1H-indene-1-subunit) malononitrile electron-withdrawing terminal A. The invention realizes the regulation and control of the photoelectric properties such as small molecular structure, absorption spectrum, band gap, front line molecular orbital level and the like by changing the type of the side chain on the IDBDT, and achieves the purpose of preparing the small molecular photoelectric functional material with excellent photoelectric properties.

(2) The invention provides a small molecule with A-D-A configuration based on IDBDT, which has a controllable absorption spectrum (300-. Meanwhile, the solar cell has good thermal stability and high open-circuit voltage, which is beneficial to obtaining a high-efficiency solar cell device.

(3) The invention provides a preparation method of a small molecule with A-D-A configuration based on IDBDT, the synthetic route has the advantages of wide raw material supply, simple and efficient synthesis and the like, and in addition, the method has high popularization and good repeatability.

(4) The invention provides an application of IDBDT-based micromolecules with A-D-A configuration in preparation of solar cells, wherein the micromolecules with A-D-A configuration are used as acceptor phase materials and donor phase materials (PBDB-T) to construct a bulk heterojunction type organic micromolecule solar cell, and the photovoltaic performance is optimized by adjusting the ratio of the acceptor to the acceptor, additives and other means. The energy conversion efficiency (PCE) obtained by PSCs based on IDBDT-T reaches 6.51 percent, and the corresponding open-circuit voltage (V)_oc) Reaches 0.97V, short-circuit current (J)_sc) Reach 12.85mA/cm²The Fill Factor (FF) reached 52.15%. The result is the first attempt of IDBDT small molecular materials in the aspect of organic solar cells, and the materials have potential research and development and application prospects in the aspect of organic photoelectric functional materials, especially organic solar cell materials.

Drawings

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention.

FIG. 1 is a diagram of the synthesis scheme of IDBDT-O, IDBDT-T in example 1 and example 2 of the present invention.

FIG. 2 is a graph showing UV-VIS absorption spectra of IDBDT-O, IDBDT-T thin films on quartz plates in Experimental example 1 and example 2 of the present invention.

FIG. 3 is a cyclic voltammogram of IDBDT-O, IDBDT-T in Experimental example 1 and example 2 of the present invention.

Fig. 4 is a structural view of a solar cell in experimental example 1 and example 2 of the present invention.

Fig. 5 is a graph of current density-voltage characteristics (J-V) of organic small molecule solar cells prepared based on IDBDT-O, IDBDT-T in experimental example 1 and example 2 of the present invention.

Detailed Description

The invention is further described below with reference to the drawings and specific preferred embodiments of the description, without thereby limiting the scope of protection of the invention. The examples described below are intended to facilitate the understanding of the invention without having any limiting effect thereon. The method is a conventional method unless otherwise specified. The reaction mass can be purchased from a publicly available commercial source unless otherwise specified.

Example 1:

an A-D-A type organic micromolecule based on nonacyclic fused aromatic hydrocarbon is specifically an A-D-A type micromolecule IDBDT-O based on IDBDT units, the IDBDT units are used as central cores D, and 2- (3-oxygen-2, 3-dihydro-1H-indene-1-subunit) malononitrile (IC) is used as electron-withdrawing terminals A.

IDBDT-O has the general structural formula of formula I:

wherein R is (2-ethylhexyl) oxy. The specific chemical structural formula of IDBDT-O is as follows:

a synthetic route of the IDBDT-O of this example is shown in fig. 1, and the specific preparation method comprises the following steps:

(1) synthesis of (4, 8-bis ((2-ethylhexyl) oxy) benzo [1,2-b:4,5-b' ] dithiophen-2-yl) tributylstannane (Compound 2).

1.1 in a 250mL three-necked flask under an argon atmosphere, 5.70g (12.76mmol) of 4, 8-bis ((2-ethylhexyl) oxy) benzo [1,2-b:4,5-b' ] dithiophene (Compound 1) and 120mL of tetrahydrofuran were added, and the reaction system was cooled to-78 ℃.

1.2, slowly dripping 6mL (14.30mmol) of n-butyllithium into a reaction bottle, reacting at-78 ℃ for 30min, and naturally recovering to room temperature for 30 min.

1.3, reducing the temperature of the reaction system to-78 ℃ again, adding 4.46mL (16.59mmol) of tributyltin chloride into the reaction bottle at one time, naturally returning to the room temperature, and reacting for 12 hours.

And 1.4, adding water to quench the reaction, extracting with petroleum ether to obtain an organic phase, drying the organic phase with anhydrous magnesium sulfate, filtering, and removing the solvent by rotation to obtain a crude product.

1.5, the crude product is a yellow liquid and is directly sent to the next step without purification.

(2) Synthesis of diethyl 2, 5-bis (4, 8-bis ((2-ethylhexyl) oxy) benzo [1,2-b:4,5-b' ] dithiophen-2-yl) terephthalate (Compound 4).

2.1 to a 250mL three-necked flask, under protection of argon (Ar), were added compound 2(20.0mmol), 1.9g (5.0mmol) of compound 3 (commercially available), 0.2g (0.15mmol) of tetrakistriphenylphosphine palladium, and 50mL of toluene in that order.

2.2, reacting the reaction system at 110 ℃ for 24 h.

2.3, reaction completion, pouring the reaction mixture into 100mL of dichloromethane, washing with water, anhydrous MgSO₄Drying, filtering and removing the solvent by spinning.

2.4, the crude product was purified by column chromatography eluting with dichloromethane and petroleum ether (1:10 by volume) to give 4.4g of a yellow solid, i.e. diethyl 2, 5-bis (4, 8-bis ((2-ethylhexyl) oxy) benzo [1,2-b:4,5-b' ] dithiophen-2-yl) terephthalate (compound 4) in yield: 79 percent. The structural characterization data for this compound is as follows:

hydrogen nuclear magnetic resonance spectroscopy:¹H NMR(CDCl₃,δ/ppm):8.01(s,1H),7.50(d,J＝4.0Hz,1H),7.46(s,1H),7.41(d,J＝8.0Hz,1H),4.27-4.19(m,6H),1.85-1.79(m,2H),1.70-1.52(m,8H),1.40-139(m,8H),1.09(t,J＝8.0Hz,3H),1.04-0.99(m,6H),0.96-0.91(m,6H)。

nuclear magnetic resonance carbon spectrum:¹³C NMR(100MHz,CDCl₃,δ/ppm):167.38,144.97,144.19,139.96,134.37,134.16,132.19,131.81,131.62,130.15,130.13,126.26,120.39,120.11,77.35,77.03,76.71,76.33,76.13,61.85,40.69,30.47,30.43,29.23,29.21,23.88,23.83,23.12,14.15,14.14,13.84,11.33,11.30.

mass spectrum: MS (MALDI-TOF, m/z) C₆₄H₈₆O₈S₄Theoretical value 1111.624; found 1110.249.

As is clear from the above, this compound has a correct structure and is diethyl 2, 5-bis (4, 8-bis ((2-ethylhexyl) oxy) benzo [1,2-b:4,5-b' ] dithiophen-2-yl) terephthalate (Compound 4).

(3) Synthesis of Compound 5

3.1 under the protection of argon (Ar), 2.9g (12.0mmol) of 1-bromo-4-hexylbenzene and 60mL of tetrahydrofuran are sequentially added into a 250mL three-necked flask, and the temperature of the reaction system is reduced to-78 ℃.

3.2, slowly dropwise adding 5.0mL (12.0mmol) of n-butyllithium into the reaction system, and after dropwise adding, keeping the temperature at-78 ℃ for reaction for 1 h.

3.3 and 2.2g (2.0mmol) of the compound 4 are dissolved in 30mL tetrahydrofuran solution, the mixed solution is slowly dripped into a reaction bottle, and the room temperature is naturally recovered after dripping, and the reaction is carried out for 12 hours.

3.4 after the reaction is completed, the reaction mixture is poured into 100mL of dichloromethane, washed with water and anhydrous MgSO₄Drying, filtering and removing the solvent by rotation to obtain a yellow crude product which is directly used for the next reaction.

3.5 under the protection of argon (Ar), 3.4 of the yellow crude product and 80mL of acetic acid are added into a 250mL three-necked flask in sequence.

3.6, heating the reaction system to 100 ℃, slowly dripping 1mL of concentrated sulfuric acid into the reaction bottle, and reacting for 4 hours.

3.7, the reaction was complete, the reaction mixture was poured into 100mL of dichloromethane, washed with water, anhydrous MgSO₄Drying, filtering and removing the solvent by spinning.

3.8, separating and purifying the crude product by column chromatography, wherein the eluent is dichloromethane and petroleum ether (1:10, volume ratio). 2.0g of a yellow solid was obtained as compound 5, yield: 62 percent. The structural characterization data for this compound is as follows:

hydrogen nuclear magnetic resonance spectroscopy:¹H NMR(CDCl₃,δ/ppm):7.41-7.38(m,5H),7.32(s,1H),7.30(d,J＝8.0Hz,1H),7.05(d,J＝8.0Hz,4H),4.16-4.09(m,2H),3.54(d,J＝4.0Hz,2H),2.54(t,J＝8.0Hz,4H),1.86-1.82(m,1H),1.74-1.71(m,1H),1.44-1.40(m,6H),1.29-1.28(m,11H),1.04(t,J＝8.0Hz,3H),0.93-0.80(m,30H)。

nuclear magnetic resonance carbon spectrum:¹³C NMR(100MHz,CDCl₃,δ/ppm):157.51,148.85,145.26,144.60,142.82,141.11,141.08,139.22,135.35,134.34,131.55,129.76,129.05,127.82,126.97,125.51,120.01,116.44,77.35,77.03,76.72,76.57,75.60,64.70,40.77,39.11,35.61,31.75,31.24,31.20,30.43,29.57,29.33,29.24,28.64,23.90,23.43,23.17,22.69,22.61,14.23,14.20,14.10,11.38,10.68.

mass spectrum: MS (MALDI-TOF, m/z) C₁₀₈H₁₄₂O₄S₄Theoretical value 1632.560; found 1631.465.

From the above, the compound has a correct structure and is compound 5.

(4) Synthesis of intermediate M1

4.1 under the protection of argon (Ar), 1.6g (1.0mmol) of the compound 5 and 60mL of tetrahydrofuran are sequentially added into a 250mL three-necked flask, and the reaction system is cooled to-78 ℃.

4.2, slowly dropwise adding 2.6mL (6.0mmol) of n-butyllithium into the reaction system, and after dropwise adding, heating the reaction system to-50 ℃ for activating reaction for 1 h.

4.3, the reaction system is cooled to-78 ℃, 0.6mL (8.0mmol) of DMF is added into the reaction bottle, and then the reaction is carried out for 24h after the room temperature is naturally recovered.

4.4, the reaction is complete, the reaction mixture is poured into 100mL of dichloromethane, washed with water, anhydrous MgSO₄Drying, filtering and removing the solvent by spinning.

4.5, the crude product is purified by column chromatography eluting with dichloromethane and petroleum ether (1:4 by volume) to give 810mg of an orange solid, compound 5, yield: 48 percent. The nuclear magnetic data are as follows:

hydrogen nuclear magnetic resonance spectroscopy:¹H NMR(CDCl₃,δ/ppm):10.05(s,1H),8.09(s,1H),7.39-7.36(m,5H),7.07(d,J＝8.0Hz,4H),4.23-4.16(m,2H),3.54(s,2H),2.57-2.53(m,4H),1.91-1.85(m,1H),1.76-1.69(m,1H),1.65-1.56(m,7H),1.34-1.28(m,15H),1.05(t,J＝8.0Hz,3H),0.98-0.92(m,6H),0.87-0.80(m,9H)。

nuclear magnetic resonance carbon spectrum:¹³C NMR(100MHz,CDCl₃,δ/ppm):184.35,158.02,149.10,147.10,145.39,145.16,141.90,141.47,141.44,138.67,135.49,134.57,131.63,131.22,130.41,128.90,127.94,116.88,77.36,77.05,76.73,75.91,64.79,40.79,39.05,35.58,31.73,31.22,31.17,30.36,29.58,29.31,29.20,28.66,23.85,23.42,23.16,22.73,22.60,14.23,14.21,14.11,11.37,10.74.

mass spectrum: MS (MALDI-TOF, m/z) C₁₁₀H₁₄₂O₆S₄Theoretical value 1688.580; found 1689.980.

From the above, the compound has a correct structure and is intermediate M1.

(5) And (3) synthesizing a small molecule IDBDT-O.

5.1 to a 100mL two-necked flask, under the protection of argon (Ar), 844mg (0.5mmol) of compound M1, 388mg (2.0mmol) of 2- (3-oxo-2, 3-dihydro-1H-inden-1-ylidene) malononitrile, 30mL of chloroform and 0.5mL of pyridine are added in this order.

5.2, reacting the reaction system at 60 ℃ for 6 h.

And 5.3, after the reaction is finished, removing the solvent by spinning, settling in absolute methanol, filtering, and separating and purifying a crude product by column chromatography, wherein an eluent is dichloromethane and petroleum ether (1:3, volume ratio) to obtain a black solid of 155mg, namely the yield of the micromolecule IDBDT-O: 23 percent. The nuclear magnetic data are as follows:

hydrogen nuclear magnetic resonance spectroscopy:¹H NMR(CDCl₃,δ/ppm):8.86(s,1H),8.65(d,J＝4.0Hz,1H),8.22(s,1H),7.92(s,1H),7.69(d,J＝4.0Hz,2H),7.41-7.37(m,5H),7.09(d,J＝8.0Hz,4H),4.24(d,J＝4.0Hz,2H),3.61(s,2H),2.55(t,J＝8.0Hz,4H),1.91-1.86(m,1H),1.75-1.70(m,1H),1.34-1.29(m,22H),1.06(t,J＝7.3Hz,3H),0.97-0.96(m,6H),0.91-0.84(m,9H)。

nuclear magnetic resonance carbon spectrum:¹³C NMR(100MHz,CDCl₃,δ/ppm):187.35,160.25,158.26,149.53,147.04,146.62,144.61,141.53,141.49,139.97,138.63,138.40,138.09,136.99,136.45,135.77,135.54,135.31,134.60,134.34,131.10,130.56,128.90,127.98,125.47,125.28,124.14,117.03,114.44,114.26,77.48,77.35,77.24,77.04,76.72,75.97,70.65,64.82,40.77,39.17,35.60,31.73,31.25,31.21,30.37,29.44,29.32,29.19,28.52,23.80,23.51,23.14,22.60,14.30,14.21,14.10,11.33,10.69.

mass spectrum: MS (MALDI-TOF, m/z) C₁₃₄H₁₅₀O₆S₄Theoretical value 2040.936; found 2040.527.

From the above, the product has a correct structure and is IDBDT-based small molecule IDBDT-O shown in structural formula I, wherein R is (2-ethylhexyl) oxy.

The micromolecule IDBDT-O prepared by the preparation method is used as an electron acceptor material in a polymer solar cell and forms a bulk heterojunction type organic solar cell together with a donor phase material PBDB-T, the structure of the cell is shown in figure 4, ITO, PEDOT: PSS, a photoactive layer, Ca and Al are sequentially arranged from a to e, and the photoactive layer is formed by blending the micromolecule IDBDT-O and the PBDB-T in a structural formula I.

The preparation method of the solar cell comprises the following steps:

(1) the anode is made of Indium Tin Oxide (ITO) conductive glass, an anode modification layer PEDOT/PSS polymer conductive film is coated on the ITO conductive glass in a spin mode, and the ITO conductive glass is processed for 15 minutes at the temperature of 150 ℃.

(2) Spin-coating an optically active layer formed by blending small molecular IDBDT-O and donor material PBDB-T (the weight ratio of PBDB-T to IDBDT-O is 1:1, and the weight ratio can be implemented between 1: 0.5 and 2).

(3) After drying for half an hour, metal calcium (about 20nm) is evaporated in vacuum to be used as a cathode modification layer.

(4) Finally, cathode metallic aluminum (about 100nm) is evaporated, and the area of the plated metal (about 4 mm) is controlled by a mask²)。

The photovoltaic performance of the organic solar cell is under simulated sunlight (AM1.5G, 100 mW/cm)²) Testing was performed by Keithley2602 table source, etc.

Example 2:

an A-D-A type organic micromolecule based on nonacyclic fused aromatic hydrocarbon is specifically an A-D-A type micromolecule IDBDT-T based on IDBDT units, the IDBDT units are used as central cores D, and 2- (3-oxygen-2, 3-dihydro-1H-indene-1-subunit) malononitrile (IC) is used as electron-withdrawing terminals A.

IDBDT-T has the general structural formula of formula I:

wherein R is 5- (2-ethylhexyl) thiophene. The specific chemical structural formula of IDBDT-T is as follows:

a synthetic route of the IDBDT-T of this example is shown in fig. 1, and the specific preparation method comprises the following steps:

(1) the procedure for the synthesis of (4, 8-bis ((2-ethylhexyl) thiophen-2-yl) benzo [1,2-b:4,5-b' ] dithiophen-2-yl) tributylstannane (Compound 2) was the same as in example 1, except that: the starting material was 4, 8-bis ((2-ethylhexyl) thiophen-2-yl) benzo [1,2-b:4,5-b' ] dithiophene, and the resulting compound 2 was used in the next step without purification.

(2) Synthesis of diethyl 2, 5-bis (4, 8-bis (5- (2-ethylhexyl) thiophen-2-yl) benzo [1,2-b:4,5-b' ] dithiophen-2-yl) terephthalate (Compound 4): same as in example 1. The nuclear magnetic data are as follows:

hydrogen nuclear magnetic resonance spectroscopy:¹H NMR(CDCl₃,δ/ppm):7.95(s,1H),7.68(d,J＝4.0Hz,1H),7.63(s,1H),7.49(d,J＝4.0Hz,1H),7.33-7.30(m,2H),6.90(t,J＝4.0Hz,2H),4.25-4.20(m,2H),2.88-2.86(m,4H),1.70-1.69(m,2H),1.48-1.42(m,16H),1.08(t,J＝6.0Hz,3H),0.97-0.90(m,12H)。

nuclear magnetic resonance carbon spectrum:¹³C NMR(100MHz,CDCl₃,δ/ppm):167.45,145.92,141.33,139.45,139.27,137.00,136.94,136.77,136.72,134.18,133.95,131.93,127.86,127.78,125.48,124.40,123.79,123.56,123.24,77.39,77.07,76.75,61.92,41.49,41.45,34.28,32.51,28.94,26.95,25.73,25.69,23.06,14.21,13.86,10.94,10.92。

mass spectrum: MS (MALDI-TOF, m/z) C₈₀H₉₄O₄S₈Theoretical value 1376.108; found 1376.145.

From the above, the compound has a correct structure and is compound 4.

(3) The synthesis of compound 5 was the same as in example 1. The nuclear magnetic data are as follows:

hydrogen nuclear magnetic resonance spectroscopy:¹H NMR(CDCl₃,δ/ppm):7.45(d,J＝8.0Hz,1H),7.32-7.29(m,2H),7.23(s,1H),7.04-7.01(m,2H),6.95-6.94(m,7H),6.35(d,J＝4.0Hz,1H),5.92(d,J＝4.0Hz,1H),2.93(d,J＝8.0Hz,2H),2.74-2.67(m,2H),2.60-2.56(m,4H),1.78-1.72(m,1H),1.41-1.34(m,23H),1.03-0.91(m,18H)。

nuclear magnetic resonance carbon spectrum:¹³C NMR(100MHz,CDCl₃,δ/ppm):159.15,149.13,146.12,146.07,145.62,145.51,145.22,143.84,140.88,140.46,138.25,137.64,137.06,137.02,136.73,135.25,134.88,132.35,129.44,128.76,128.52,128.00,127.96,127.86,125.70,125.39,124.26,123.94,122.65,115.85,77.41,77.09,76.78,64.17,41.51,41.22,35.69,35.56,34.34,34.09,34.04,32.58,32.52,32.44,31.88,31.86,31.63,29.32,29.14,29.03,28.86,25.82,25.70,25.55,23.30,23.20,23.13,22.72,14.35,14.33,14.27,14.22,10.98,10.94,10.90

mass spectrum: MS (MALDI-TOF, m/z) C₁₂₄H₁₅₀S₈Theoretical value 1897.044; found 1897.369.

From the above, the compound has a correct structure and is compound 5.

(4) The synthesis of intermediate M1 was the same as in example 1. The nuclear magnetic data are as follows:

hydrogen nuclear magnetic resonance spectroscopy:¹H NMR(CDCl₃,δ/ppm):9.92(s,1H),8.09(s,1H),7.30(d,J＝3.4Hz,1H),7.20(s,1H),6.94-6.90(m,9H),6.31(d,J＝4.0Hz,1H),5.86(d,J＝4.0Hz,1H),2.90(d,J＝8.0Hz,2H),2.67-2.62(m,2H),2.60-2.51(m,4H),1.72-1.69(m,1H),1.47-1.28(m,23H),0.99-0.84(m,18H)。

nuclear magnetic resonance carbon spectrum:¹³C NMR(100MHz,CDCl₃,δ/ppm):184.60,159.56,149.39,148.76,147.86,147.07,146.28,144.44,143.39,141.13,140.84,137.70,137.19,135.71,135.42,135.09,134.05,133.64,129.92,128.60,128.41,128.10,127.94,125.67,124.46,116.27,77.36,77.05,76.73,64.24,41.49,41.15,35.62,35.49,34.31,34.01,32.53,32.45,31.80,31.54,29.26,29.11,28.97,28.80,25.80,25.65,25.50,23.24,23.13,23.07,22.67,14.22,14.15,10.92,10.82。

mass spectrum: MS (MALDI-TOF, m/z) C₁₂₆H₁₅O₂S₈Theoretical value 1953.064; found 1953.229.

From the above, the compound has a correct structure and is intermediate M1.

(5) The synthesis process of the small molecule IDBDT-T is the same as in example 1. The nuclear magnetic data are as follows:

hydrogen nuclear magnetic resonance spectroscopy:¹H NMR(CDCl₃,δ/ppm):8.76(s,1H),8.67(d,J＝8.0Hz,1H),8.24(s,1H),7.83(d,J＝8.0Hz,1H),7.76-7.70(m,2H),7.34(s,1H),7.23(s,1H),6.97-6.90(m,9H),6.39(d,J＝4.0Hz,1H),5.93(d,J＝4.0Hz,1H),2.92(d,J＝8.0Hz,2H),2.74-2.66(m,2H),2.53(d,J＝4.0Hz,4H),1.75-1.70(m,1H),1.38-1.31(m,23H),0.98-0.86(m,18H)

nuclear magnetic resonance carbon spectrum:¹³C NMR(100MHz,CDCl₃,δ/ppm):187.09,160.42,159.79,151.53,150.02,149.81,147.36,146.26,144.56,141.41,141.27,140.79,139.97,138.76,138.12,137.64,137.08,137.03,135.73,135.29,135.25,134.62,134.11,129.94,128.78,128.64,128.38,128.30,128.12,127.96,125.83,125.45,125.29,124.65,124.02,123.68,116.41,114.45,114.19,77.35,77.24,77.03,76.72,70.57,64.26,41.59,41.45,41.25,35.63,35.52,34.37,32.58,32.36,31.79,31.57,29.24,28.98,28.85,25.78,25.59,25.53,23.23,23.13,23.08,22.66,22.64,14.32,14.23,14.15,11.04,10.92

mass spectrum: MS (MALDI-TOF, m/z) C₁₅₀H₁₅₈O₂S₈Theoretical value 2305.420; found 2304.565.

From the above, the product has a correct structure and is IDBDT-based small molecule IDBDT-T shown in structural formula I, wherein R is 5- (2-ethylhexyl) thiophene.

The micromolecule IDBDT-T prepared by the method is used as an acceptor material in an organic solar cell and forms a bulk heterojunction type organic solar cell together with a donor phase material, the structure of the cell is shown in figure 4, the structure is shown in the figure, the structure from a to e is ITO, PEDOT: PSS, a photoactive layer, Ca and Al, and the photoactive layer is formed by blending the micromolecule IDBDT-T with the PBDB-T, wherein the micromolecule IDBDT-T is shown in the structural formula I.

The preparation method of the solar cell comprises the following steps:

(1) the anode is made of Indium Tin Oxide (ITO) conductive glass, an anode modification layer PEDOT/PSS polymer conductive film is coated on the ITO conductive glass in a spin mode, and the ITO conductive glass is processed for 15 minutes at the temperature of 150 ℃.

(2) And spin-coating an optically active layer formed by blending micromolecular IDBDT-T and donor material PBDB-T (the weight ratio of PBDB-T to IDBDT-T is 1:1, and the weight ratio can be implemented between 1: 0.5 and 2).

(3) After drying for half an hour, metal calcium (about 20nm) is evaporated in vacuum to be used as a cathode modification layer.

(4) Finally, cathode metallic aluminum (about 100nm) is evaporated, and the area of the plated metal (about 4 mm) is controlled by a mask²)。

The photovoltaic performance of the organic solar cell is under simulated sunlight (AM1.5G, 100 mW/cm)²) Testing was performed by Keithley2602 table source, etc.

And (4) result characterization:

the spectral, electrochemical and photovoltaic properties were determined as follows:

(1) spectral properties of the Small molecules IDBDT-O and IDBDT-T

FIG. 2 shows UV-visible absorption spectra of small molecule IDBDT-O and IDBDT-T films on a quartz plate. According to the ultraviolet-visible absorption spectrum, the absorption side band values (lambda) of the small molecules IDBDT-O and IDBDT-T on the quartz plate are respectively 802nm and 762 nm. According to empirical formula E_g ^optThe corresponding optical band gaps of the polymer were calculated to be 1.55 and 1.63eV, respectively, 1240/λ.

(2) Electrochemical Properties of Small molecules IDBDT-O and IDBDT-T

FIG. 3 is a cyclic voltammogram of small molecules IDBDT-O and IDBDT-T. And (3) testing by adopting a three-electrode system: the working electrode is a platinum electrode coated with micromolecules IDBDT-O and IDBDT-T films in a blade mode, the platinum wire is a counter electrode, Ag/AgCl is a reference electrode, and Bu₄NPF₆As a supporting electrolyte, ferrocene redox couple is used as an internal standard. The test conditions were: the scanning range is-1.6V (vs. Ag/AgCl), and the scanning speed is 100 mV/s.

The HOMO/LUMO energy levels of the small molecules IDBDT-O and IDBDT-T are respectively-5.66/-3.68 eV and-5.59/-3.60 eV calculated according to the cyclic voltammogram. Since the small molecule IDBDT cell in this embodiment has an electron donating ability, the LUMO energy levels of the two small molecules in this embodiment are relatively high, which is advantageous for obtaining a high open circuit voltage of the battery.

(3) Photovoltaic properties of organic small molecule solar cells of small molecule IDBDT-O and IDBDT-T

The prepared micromolecules can be used as an acceptor material in an organic micromolecule solar cell, and the micromolecules and a donor phase material form a bulk heterojunction type organic solar cell together, the structure of the cell is ITO/PEDOT: PSS/photoactive layer/Ca/Al, as shown in figure 4, the photoactive layer is formed by blending any one of the micromolecules obtained in examples 1 and 2 and PBDB-T. Wherein

Figure 4 is the reference number: a-base anode, b-anode modifying layer, c-mixed active layer of donor material and acceptor material, d-cathode modifying layer and e-cathode.

In the organic micromolecule bulk heterojunction type solar cell prepared by the invention, indium tin oxide conductive glass (ITO) is adopted as an anode, an anode modification layer PEDOT, namely a PSS polymer conductive film, is spin-coated on the ITO,treating at 150 deg.C for 15 min, spin-coating a photoactive layer prepared by blending prepared micromolecules and donor material PBDB-T, vacuum evaporating metal calcium (about 20nm) as cathode modification layer after drying for half an hour, evaporating cathode metal aluminum (about 100nm), and controlling the area of the metal (about 4 mm) by mask²). The photovoltaic performance of the organic micromolecule solar cell device is under simulated sunlight (AM1.5G, 100 mW/cm)²) Testing was performed by Keithley2602 table source, etc.

Fig. 5 is a current density-voltage characteristic (J-V) curve of the resulting organic small molecule solar cell prepared based on one of two small molecules. The optimal photovoltaic performance of the photovoltaic device corresponding to the graph is as follows:

IDBDT-O: energy conversion efficiency (PCE) — 1.49%, open circuit voltage (V)_oc) 0.85V, short-circuit current (J)_sc)＝4.19mA/cm²The Fill Factor (FF) is 41.64%.

IDBDT-T: energy conversion efficiency (PCE) 6.51%, open circuit voltage (V)_oc) 0.97V, short-circuit current (J)_sc)＝12.82mA/cm²The Fill Factor (FF) is 52.15%.

The invention takes synthesized IDBDT-based micromolecules with different side chains as the photoactive layer of the organic solar cell to prepare a plurality of polymer solar cell devices. The highest energy conversion efficiency reaches 6.51%, the open-circuit voltage is as high as 0.97V, and the filling factor reaches 52.15%. All experimental results show that the IDBDT-based micromolecule provided by the invention is an excellent micromolecule solar cell receptor material and shows potential application value in the aspect of organic solar cells. The invention not only has simple and effective synthesis method, but also prepares a series of A-D-A type micromolecule receptor materials based on IDBDT. The method has very important significance for researching the relationship between the structure and the performance of the micromolecule solar cell material, and can further guide the development of the micromolecule solar cell material with high photoelectric property.

The foregoing is merely a preferred embodiment of the invention and is not intended to limit the invention in any manner. Although the present invention has been described with reference to the preferred embodiments, it is not intended to be limited thereto. Those skilled in the art can make many possible variations and modifications to the disclosed embodiments, or equivalent modifications, without departing from the spirit and scope of the invention, using the methods and techniques disclosed above. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above embodiments according to the technical essence of the present invention are still within the scope of the protection of the technical solution of the present invention.

Claims (10)

1. A-D-A type organic small molecule based on nine-ring fused aromatic hydrocarbon is characterized in that the A-D-A type organic small molecule has a structural formula shown as the following formula I:

in the formula I: r is selected from any one of the following groups:

-C₆H₁₃、-C₈H₁₇、-C₁₀H₂₁、-C₁₂H₂₅、-C₁₄H₂₉、-OC₆H₁₃、-OC₈H₁₇、-OC₁₀H₂₁、-OC₁₂H₂₅、-OC₁₄H₂₉、

2. the method for preparing the nonacyclic fused aromatic hydrocarbon-based small organic molecule of type A-D-A according to claim 1, wherein the small organic molecule of type A-D-A is obtained by performing Knoevenagel condensation reaction on intermediate M1 and 2- (3-oxo-2, 3-dihydro-1H-indene-1-ylidene) malononitrile in the presence of a solvent and a catalyst, wherein the 2- (3-oxo-2, 3-dihydro-1H-indene-1-ylidene) malononitrile is denoted as IC, and the intermediate M1 has a structural formula shown in formula II below:

in the formula II: r is selected from any one of the following groups:

-C₆H₁₃、-C₈H₁₇、-C₁₀H₂₁、-C₁₂H₂₅、-C₁₄H₂₉、-OC₆H₁₃、-OC₈H₁₇、-OC₁₀H₂₁、-OC₁₂H₂₅、-OC₁₄H₂₉、

3. the preparation method of claim 2, wherein the molar ratio of the intermediate M1 to IC is 1: 4-6;

and/or the molar ratio of the catalyst to the intermediate M1 is 11-14: 1;

and/or the catalyst is one of pyridine, piperidine and triethylamine;

and/or the solvent is one of trichloromethane and acetonitrile.

4. The preparation method according to claim 2 or 3, wherein the intermediate M1 is prepared by the following method:

s1-1, reacting the compound 1 with n-butyl lithium and tributyl tin chloride at-78 ℃ to obtain a compound 2;

s1-2, mixing the compound 2, the compound 3 and tetratriphenylphosphine palladium, and heating to react to obtain a compound 4;

s1-3, reacting the compound 4 with n-butyllithium and 1-bromo-4-hexylbenzene at-78 ℃ to obtain a compound 5;

s1-4, reacting the compound 5 with N-butyllithium and N, N-dimethylacetamide at-78 ℃ to obtain an intermediate M1;

the compound 1 is

The compound 2 is;

the compound 3 is:

the compound 4 is:

the compound 5 is:

the compound M1 is:

5. the preparation method according to claim 4, wherein in S1-1, the compound 1, n-butyllithium and tributyltin chloride are present in a molar ratio of 1:1 to 2.

6. The preparation method according to claim 4, wherein in S1-2, the molar ratio of the compound 2 to the compound 3 to the tetrakistriphenylphosphine palladium is 3-4: 1: 0.03-0.05.

7. The preparation method according to claim 4, wherein in S1-3, the molar ratio of the compound 4, n-butyllithium and 1-bromo-4-hexylbenzene is 1: 4-6: 5-7.

8. The preparation method according to claim 4, wherein in S1-4, the molar ratio of the compound 5, N-butyllithium and N, N-dimethylacetamide is 1: 4-8: 6-10.

9. Application of the A-D-A type organic small molecule based on the nonacyclic fused aromatic hydrocarbon according to claim 1 or the A-D-A type organic small molecule based on the nonacyclic fused aromatic hydrocarbon prepared by the preparation method according to any one of claims 2 to 8 in preparation of solar cells.

10. The application according to claim 9, wherein the method of application is:

(1) spin-coating a conductive film of PEDOT/PSS polymer on the anode;

(2) spin-coating an optically active layer formed by blending A-D-A type organic micromolecules based on the nine-ring fused aromatic hydrocarbon and PBDB-T;

(3) vacuum evaporating metal calcium as a cathode modification layer;

(4) and evaporating cathode metal aluminum to obtain the solar cell.